Section-j: mf-hf Equip. And Comms: Key Topic #81: mf-hf Frequency–Simplex, Duplex, Half-Duplex:

81J1 How are paired SITOR (NBDP) frequencies normally used?

A. These are normally used for ARQ communications with coast radio stations.

B. These are normally used for FEC communications with coast radio stations.

C. These are normally used only for Distress communications to limit channel interference.

D. These are normally used for DSC communications with coast radio stations.

81J2 How are paired SSB frequencies normally used?

A. These are normally used for FEC communications with coast radio stations.

B. These are normally used for J3E communications with coast radio stations.

C. These are normally used for ARQ communications with coast radio stations.

D. These are normally used for DSC communications with coast radio stations.

81J3 For general communications purposes, paired frequencies are:

A. Normally used with private coast stations.

B. Normally used between ship stations.

C. Normally used with public coast stations.

D. Normally used between private coast and ship stations.

81J4 For general communications purposes, simplex frequencies are:

A. Normally used with public coast stations for routine telephone communications.

B. Normally used between ship stations as well as public coast stations simultaneously.

C. Normally used with public coast stations for routine SITOR (NBDP) communications.

D. Normally used between ship stations and private coast stations or for ship-ship communications.

81J5 An ITU simplex channel frequency assignment is defined as:

A. Transmit and receive frequencies must be identical.

B. Transmit and receive frequencies must be different.

C. Transmit and receive frequencies may be different, depending on whether communications are ship-shore or ship to ship.

D. Transmit and receive frequencies are different regardless of emission mode.

81J6 An ITU duplex channel frequency is defined as:

A. Transmit and receive frequencies may be identical if communications are ship-shore.

B. Transmit and receive frequencies must be different.

C. Transmit and receive frequencies must be identical.

D. Transmit and receive frequencies may be different if communications are ship-ship.

Answers: 81J1 - A 81J2 - B 81J3 - C 81J4 - D 81J5 - A 81J6 - B

Section-j: mf-hf Equip. And Comms: Key Topic #82: mf-hf itu Channels:

82J1 Which of the following defines "ITU Channel 1216"?

A. Ch-12 in the 16 MHz band.

B. Ch-1216 in the MF band.

C. Ch-12 in the 16 kHz band.

D. Ch-16 in the 12 MHz band.

82J2 Which of the following is a valid 22-MHz ITU Channel?

A. HF Ch-2206

B. VHF Ch-22

C. Ch-22A VTS

D. Ch-70 (DSC only)

82J3 What is meant by the term duplex "ITU channel"?

A. This refers to a vessel's SELCAL number.

B. A standardized series of frequency pairings for common use.

C. This refers to VHF channels 1-28 and 60-88.

D. A series of frequency pairings used for ship-ship communications.

82J4 ITU duplex channel 1604 would mean:

A. Ch-16 in the 4 MHz band.

B. Ch-1604 in the MF band.

C. Ch-4 in the 16 MHz band.

D. Ch-4 in the 6 MHz band.

82J5 What is a potential danger of using the manufacturer’s database to set up for operations using MF-HF ITU frequency assignments?

A. All manufacturer’s frequency databases are required to be standardized & accurate so that there is no danger.

B. Using the manufacturer’s frequency database to setup the transceiver typically takes longer and is more prone to error than a manual setup.

C. Different manufacturers use different database numbering systems to incorporate the ITU assignments into the transceiver and therefore a potential for confusion exists.

D. Using the manufacturer’s frequency databases ensures that the transceiver is always restricted to the vessel’s licensed frequencies so that there is no danger.

82J6 ITU Duplex channels are:

A. Frequency assignments specific to U.S. vessels only.

B. VHF-FM frequencies.

C. International Traffic Utility frequencies.

D. Internationally standardized assignments of frequency pairs for common use.

Answers: 82J1 - D 82J2 - A 82J3 - B 82J4 - C 82J5 - C 82J6 - D